Gas injection system and reactor system including same

ABSTRACT

A gas injection system, a reactor system including the gas injection system, and methods of using the gas injection system and reactor system are disclosed. The gas injection system can be used in gas-phase reactor systems to independently monitor and control gas flow rates in a plurality of channels of a gas injection system coupled to a reaction chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Non-provisional of, and claims priority to and thebenefit of, U.S. Provisional Patent Application No. 62/912,521, filedOct. 8, 2019 and entitled “GAS INJECTION SYSTEM AND REACTOR SYSTEMINCLUDING SAME,” which is hereby incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to gas-phase reactors andsystems. More particularly, the disclosure relates to gas injectionsystems for introducing gas to a reaction chamber, to reactors andreactor systems including a gas injection system, and to methods ofusing same.

BACKGROUND OF THE DISCLOSURE

Gas-phase reactors, such as chemical vapor deposition (CVD),plasma-enhanced CVD (PECVD), and atomic layer deposition (ALD) reactorscan be used for a variety of applications, including depositing andetching materials on a substrate surface and/or cleaning a substratesurface. For example, gas-phase reactors can be used to deposit and/oretch layers on a substrate to form semiconductor devices, flat paneldisplay devices, photovoltaic devices, microelectromechanical systems(MEMS), and the like.

A typical gas-phase reactor system includes a reactor including areaction chamber, one or more precursor and/or reactant gas sourcesfluidly coupled to the reaction chamber, one or more carrier and/orpurge gas sources fluidly coupled to the reaction chamber, a gasinjection system to deliver gases (e.g., precursor/reactant gas(es)and/or carrier/purge gas(es)) to the reaction chamber, and an exhaustsource fluidly coupled to the reaction chamber.

Generally, it is desirable to have uniform film properties (e.g., filmthickness and film composition) across a surface of a substrate and/orto have control over any desired variation of the film properties. Assizes of features formed on a substrate surface decrease, it becomesincreasingly important to control film properties, such as filmthickness, composition, and resistivity. Moreover, it may be desirableto independently tune film properties; e.g., to independently tune filmthickness uniformity and/or composition in layers deposited usinggas-phase reactors, such as epitaxial layers grown using such reactors.Accordingly, gas injection systems, reactor systems including the gasinjection systems, and methods of using the gas injection and reactorsystems, which allow for desired control and manipulation of parametersthat lead to desired film properties, are desired.

Any discussion, including discussion of problems and solutions, setforth in this section has been included in this disclosure solely forthe purpose of providing a context for the present disclosure, andshould not be taken as an admission that any or all of the discussionwas known at the time the invention was made or otherwise constitutesprior art.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to necessarily identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Various embodiments of the present disclosure relate to gas injectionsystems, reactor systems including a gas injection system, and tomethods of using the gas injection systems and reactor systems. Whilethe ways in which various embodiments of the present disclosure addressdrawbacks of prior gas injection systems and reactor systems arediscussed in more detail below, in general, various embodiments of thedisclosure provide gas injection systems that can provide improvedcontrol of film thickness and/or film composition across a surface of asubstrate. As set forth in more detail below, examples of the disclosuremay be particularly useful for forming doped epitaxial layers on asurface of a substrate. Exemplary systems and methods can allow finetuning of precursor and dopant flowrates to a reaction chamber and/or asubstrate surface to allow formation of films with desired thicknessand/or composition uniformity and/or variation. For example, in somecases, it may be desirable to form films with desired compositionvariation—rather than to form a film with uniform composition across asubstrate surface.

In accordance with exemplary embodiments of the disclosure, a gasinjection system includes a first gas manifold comprising a first gasinlet and a plurality of first gas outlets; a second gas manifoldcomprising a second gas inlet and a plurality of second gas outlets; aplurality of first gas valves, wherein each of the plurality of firstgas outlets is coupled to at least one of the plurality of first gasvalves; and a plurality of second gas valves, wherein each of theplurality of second gas outlets is coupled to at least one of theplurality of second gas valves. The first gas inlet can receive a firstgas comprising a first precursor and a dopant. The second gas inlet canreceive a second gas comprising the first precursor or a secondprecursor and an etchant. In accordance with some examples of thedisclosure, the second gas includes the first precursor. A chemicalformula of the first precursor and a chemical formula of the secondprecursor can comprise one or more or all of the same elements. The gasinjection system can further include a first flow controller coupled toa first precursor source and the first gas inlet and a second flowcontroller coupled to the first precursor source and the second gasinlet.

In accordance with additional embodiments of the disclosure, a gasinjection system includes a first gas manifold comprising a first gasinlet and a plurality of first gas outlets; a second gas manifoldcomprising a second gas inlet and a plurality of second gas outlets; aplurality of first gas valves, wherein each of the plurality of firstgas outlets is coupled to at least one of the plurality of first gasvalves; and a plurality of second gas valves, wherein each of theplurality of second gas outlets is coupled to at least one of theplurality of second gas valves, wherein the first gas inlet receives afirst gas comprising an etchant and a dopant. The second gas inlet canreceive a second gas comprising a precursor. The first and/or second gascan include a carrier gas. The gas injection system can include a flowcontroller to control a flowrate of a carrier gas to the first and/orsecond gas inlet.

In accordance with additional exemplary embodiments of the disclosure, agas-phase reactor system includes one or more gas injection systems asdescribed herein. Exemplary systems can also include an exhaust (e.g.,vacuum) source coupled to the reaction chamber, a first gas sourcefluidly coupled to the one or more first gas channels, and a second gassource fluidly coupled to the one or more second gas channels. Exemplarysystems can also include additional gas and/or exhaust sources.

In accordance with yet additional exemplary embodiments of thedisclosure, a method is provided. Exemplary methods include depositingmaterial on a surface of a substrate using a gas injection system and/ora reactor system as described herein. Exemplary methods can includeautomatically adjusting one or more valves coupled to the one or morefirst gas outlets and/or automatically adjusting one or more valvescoupled to the one or more second gas outlets. Exemplary methods canalso include a step of providing an asymmetric setting of one or more ofa first gas from the first gas source and a second gas from the secondgas source—to, e.g., tune (e.g., independently) film properties, such asfilm thickness, film thickness uniformity, and film composition across asurface of a substrate, including an edge region of the substrate, andthe like. In accordance with some examples, a method includes a step ofrotating a susceptor at a rotational speed of about 60 to about 30, orabout 30 to about 15, or about 15 to about 5 rotations per minute.

These and other embodiments will become readily apparent to thoseskilled in the art from the following detailed description of certainembodiments having reference to the attached figures; the disclosure notbeing limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of exemplary embodiments of the presentdisclosure can be derived by referring to the detailed description andclaims when considered in connection with the following illustrativefigures.

FIG. 1 illustrates a reactor system in accordance with at least oneexemplary embodiment of the present disclosure.

FIG. 2 schematically illustrates a gas injection system in accordancewith at least one exemplary embodiment of the disclosure.

FIG. 3 illustrates a cross-sectional view of a flange in accordance withat least one exemplary embodiment of the disclosure.

FIG. 4 schematically illustrates a portion of a reactor system inaccordance with at least one exemplary embodiment of the disclosure.

FIGS. 5A and 5B illustrate charts depicting characteristics of silicongermanium layers deposited on a substrate in accordance with at leastone exemplary embodiment of the disclosure.

FIG. 6 illustrates charts depicting characteristics of another silicongermanium layer deposited on a substrate in accordance with at least oneexemplary embodiment of the disclosure.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help to improve theunderstanding of illustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE DISCLOSURE

The description of exemplary embodiments provided below is merelyexemplary and is intended for purposes of illustration only; thefollowing description is not intended to limit the scope of thedisclosure or the claims. Moreover, recitation of multiple embodimentshaving stated features is not intended to exclude other embodimentshaving additional features or other embodiments incorporating differentcombinations of the stated features.

The present disclosure generally relates to gas injection systems, toreactors and reactor systems including a gas injection system, and tomethods of using the gas injection systems and reactor systems. Gasinjection systems, reactors, and reactor systems including a gasinjection system as described herein, can be used to process substrates,such as semiconductor wafers. By way of examples, the systems describedherein can be used to form or grow epitaxial layers (e.g., two-componentand/or doped semiconductor layers) on a surface of a substrate.Exemplary systems can be further used to provide etch chemistry to asubstrate surface. For example, exemplary systems can provide a mixtureof two or more gases (e.g., collectively referred to herein as a mixtureor simply gas or first gas or second gas) during a deposition (e.g.,growth) process. For example, a first gas can include a first precursorand/or a dopant, and a second gas can include the first precursor and/ora second precursor and/or an etchant, or a first gas can include anetchant and/or a dopant, and a second gas can include a precursor. Theetchant can be used to facilitate desired film deposition and/or tofacilitate selective deposition of the film overlying a firstmaterial/surface on a substrate surface relative to deposition of thefilm overlying a second material/surface of the substrate. Exemplary gasinjection systems, reactor systems, and methods described herein, may beparticularly useful in forming films having relatively high dopantconcentrations (e.g., greater than about 30 percent, about 20 percent orabout 10 percent).

As set forth in more detail below, use of exemplary gas injectionsystems as described herein is advantageous, because it allowsindependent metering and control of gas (e.g., a gas mixture) flowthrough various channels of the gas injection systems, and, in turn, toinput sites of a reaction chamber. The independent control of gas flowcan, in turn, allow independent tuning of film properties of films thatare formed using a reactor system including the gas injection system.For example, an exemplary gas injection system can be used toindependently tune dopant concentration profiles and film thickness (orthickness uniformity) of, for example, epitaxially formed layers on asubstrate. Additionally or alternatively, exemplary gas injectionsystems can be used to compensate for gas flow variations, depletionrate variations, auto doping, variations in dopant profiles that mightotherwise occur because of features on a substrate surface, orcombinations thereof that may otherwise occur within a reaction chamberof a reactor system. For example, the independent gas flow control atvarious input sites can be used to compensate for, or mitigate against,undesired edge effects (e.g., to mitigate against edge roll-down, i.e.,a decrease in the rate of layer thickness increase toward the edge of asubstrate) and/or undesired effects of a rotating substrate, which mightotherwise cause undesired nonuniformity or other characteristics in oneor more film properties. Exemplary gas injection systems are scalable toany desired number of channels and can be used with gas mixtures, whilemaintaining desired precision and control of flow rates (e.g.,independent of the makeup of the gas mixture). Additionally, exemplarygas injection systems of the present disclosure can be used forrelatively high gas flow rates (e.g., greater than five standard litersper minute of nitrogen through each channel) and/or can operate atrelatively high (e.g., near atmospheric) pressures, if desired. Theseand other features of the systems and methods described herein can beparticularly useful in depositing high-quality epitaxial layers onsubstrates.

As used herein, the terms precursor and/or reactant can refer to one ormore gases/vapors that take part in a chemical reaction or from which agas-phase substance that takes part in a reaction is derived. Thechemical reaction can take place in the gas phase and/or between a gasphase and a surface of a substrate and/or a species on a surface of asubstrate.

As used herein, a substrate can refer to any material having a surfaceonto which material can be deposited. A substrate can include a bulkmaterial such as silicon (e.g., single crystal silicon) or may includeone or more layers overlying the bulk material. Further, the substratemay include various topologies, such as trenches, vias, lines, and thelike formed within or on at least a portion of a layer of the substrate.

As used herein, the term epitaxial layer can refer to a substantiallysingle crystalline layer upon an underlying substantially singlecrystalline substrate or layer.

As used herein, the term chemical vapor deposition can refer to anyprocess wherein a substrate is exposed to one or more gas-phaseprecursors, which react and/or decompose on a substrate surface toproduce a desired deposition.

As used herein, the terms film and/or layer can refer to any continuousor non-continuous structures and material, such as material deposited bythe methods disclosed herein. For example, film and/or layer can includetwo-dimensional materials, three-dimensional materials, nanoparticles oreven partial or full molecular layers or partial or full atomic layersor clusters of atoms and/or molecules. A film or layer may comprisematerial or a layer with pinholes, which may be at least partiallycontinuous.

As used herein, the term structure can refer to a substrate as describedherein, and/or a substrate including one or more layers overlying thesubstrate, such as one or more layers formed according to a method asdescribed herein.

Further, in this disclosure, any two numbers of a variable canconstitute a workable range of the variable, and any ranges indicatedmay include or exclude the endpoints. Additionally, any values ofvariables indicated (regardless of whether they are indicated with“about” or not) may refer to precise values or approximate values andinclude equivalents, and may refer to average, median, representative,majority, or the like. Further, in this disclosure, the terms“including,” “constituted by” and “having” refer independently to“typically or broadly comprising,” “comprising,” “consisting essentiallyof,” or “consisting of” in some embodiments. In this disclosure, anydefined meanings do not necessarily exclude ordinary and customarymeanings in some embodiments.

Turning now to the figures, FIG. 1 illustrates an exemplary reactorsystem 100. Reactor system 100 can be used for a variety ofapplications, such as, for example, chemical vapor deposition (CVD),plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), cleanprocesses, etch processes, and the like. Although exemplary embodimentsare described below in connection with epitaxial reactor systems,embodiments and the disclosure are not so limited, unless statedotherwise.

In the illustrated example, reactor system 100 includes an optionalsubstrate handling system 102, a reaction chamber 104, a gas injectionsystem 106, and optionally a wall 108 disposed between reaction chamber104 and substrate handling system 102. System 100 can also include afirst gas source 112, a second gas source 114, an exhaust source 110,and a susceptor or substrate support 116. Although illustrated with twogas sources 112, 114, reactor system 100 can include any suitable numberof gas sources. Further, reactor system 100 can include any suitablenumber of reaction chambers 104, which can each be coupled to a gasinjection system 106. In the case in which reactor system 100 includesmultiple reaction chambers, each gas injection system can be coupled tothe same gas sources 112, 114 or to different gas sources.

Gas sources 112, 114 can include a compound or a combination ofcompounds for delivery to reaction chamber 104. For example, gas sources112, 114 can include various combinations of one or more precursors, oneor more dopant sources, one or more etchants, and mixtures of gases,including mixtures of one or more precursors, dopant sources, and/oretchants with one or more carrier gases.

By way of examples, first gas source 112 can include an etchant and adopant source. Second gas source 114 can include a precursor.Alternatively, first gas source 112 can include an etchant and a dopantsource; second gas source 114 can include a precursor. As anotherexample, first gas source 112 can include a first precursor, a secondprecursor, and/or an etchant, and the second gas source 114 can includethe first precursor and/or an etchant. The etchant comprised in firstgas source 112 and second gas source 114 may be the same compound. Invarious embodiments, first gas source 112 and second gas source 114 mayhave at least one component (e.g., a precursor, etchant, etc.) incommon.

Exemplary etchants can include a halide, such as a chlorine-containinggas. Exemplary chlorine-containing gases include one or more gasesselected from the group consisting of hydrogen chloride, chlorine gas,and the like.

Exemplary precursors include silicon-containing precursors, such astrichlorosilane, dichlorosilane, silane, disilane, trisilane, silicontetrachloride, and the like, and/or germanium-containing precursors,such as germane (GeH₄), digermane (Ge₂H₆), trigermane (Ge₃H₈), and thelike.

Exemplary dopant sources include gases that include one or more of As,P, C, Ge, and B. By way of examples, the dopant source can includegermane, diborane, phosphine, arsine, phosphorus trichloride. The gasinjection systems, reactor systems, and methods described herein may beparticularly useful in forming p-type doped films, such as p-type dopedfilms comprising silicon, silicon germanium, or the like.

Carrier gases can be or include one or more inert gases and/or hydrogen.Exemplary carrier gases include one or more gases selected from thegroup consisting of hydrogen, nitrogen, argon, helium, or the like.

When the first gas includes a first precursor and a dopant source, thefirst gas can include from about 30 to about 5 or about 15 to about 5volumetric percent first precursor and/or from about 15 to about 5 orabout 10 to about 5 volumetric percent dopant source. First gas sourcecan also include from about 75 to about 95 or about 85 to about 90volumetric percent carrier gas.

When the first gas includes an etchant and a dopant source, the firstgas can include from about 25 to about 5, about 20 to about 5, or about15 to about 5 volumetric percent etchant and/or from about 25 to about5, about 20 to about 5, or about 15 to about 5 volumetric percent dopantsource. First gas source can also include from about 60 to about 95,about 70 to about 90, or about 75 to about 85 volumetric percent carriergas.

When the second gas includes the first precursor and/or a secondprecursor and an etchant, the first gas can include from about 0 toabout 20 or about 5 to about 15 volumetric percent first and/or secondprecursor and/or from about 0 to about 7 or about 2 to about 5volumetric percent etchant. Second gas source can also include fromabout 75 to about 95 or about 85 to about 95 volumetric percent carriergas.

When the second gas includes a precursor, the first gas can include fromabout 5 to about 20 or about 5 to about 15 volumetric percent precursor.Second gas source can also include from about 75 to about 95 or about 85to about 95 volumetric percent carrier gas.

Reactor system 100 can include any suitable number of reaction chambers104 and substrate handling systems 102. Reaction chamber 104 of reactorsystem 100 can be or include, for example, a cross flow, cold wallepitaxial reaction chamber.

Susceptor or substrate support 116 can include one or more heaters 118to heat a substrate 120—e.g., to a temperature of about 500 to about600, about 600 to about 700, or about 700 to about 800 degrees Celsius.Susceptor or substrate support 116 can also be configured to rotateduring processing. In accordance with examples of the disclosure,susceptor or substrate support 116 rotates at a speed of about 60 toabout 30, about 30 to about 15, or about 15 to about 5 rotations perminute.

During operation of reactor system 100, substrates 120, such assemiconductor wafers, are transferred from, e.g., substrate handlingsystem 102, to reaction chamber 104. Once substrate(s) 120 aretransferred to reaction chamber 104, one or more gases from first andsecond gas sources 112, 114, such as precursors, dopants, carrier gases,etchants, and/or purge gases are introduced into reaction chamber 104via gas injection system 106. As set forth in more detail below, gasinjection system 106 can be used to meter and control gas flow of one ormore gases from first gas source 112 and second gas source 114 duringsubstrate processing and to provide desired flows of such gas(es) tomultiple sites within reaction chamber 104.

FIG. 2 schematically illustrates a gas injection system 200, suitablefor use as gas injection system 106, in accordance with exemplaryembodiments of the disclosure. Gas injection system 200 includes a firstgas supply line 202 coupled to a first gas source 203, which can be thesame or similar to gas source 112, and a second gas supply line 204coupled to a second gas source 205, which can be the same or similar togas source 114. When referring to gas lines and fluid components of gasinjection system 200, the term coupled refers to fluidly coupled, and,unless stated otherwise, the lines or components need not be directlyfluidly coupled, but rather gas injection system 200 can include otherintervening elements, such as connectors, valves, meters, or the like.

Gas injection system 200 includes a first gas manifold 206 coupled tofirst gas supply line 202 via a first gas inlet 215 and a second gasmanifold 208 coupled to second gas supply line 204 via a second gasinlet 217. First gas manifold 206 includes a plurality of first gasoutlets 210-218. Similarly, second gas manifold 208 includes a pluralityof second gas outlets 220-228. First gas manifold 206 and second gasmanifold 208 are configured to receive gas from one or more gas lines(e.g., first and second gas lines 202, 204) and distribute the gas intoone or more channels, which are respectively defined, in part, by firstgas outlets 208-218 and second gas outlets 220-228. In the illustratedexample, each of the first and second gas streams from first gas source203 and second gas source 205 is divided into five gas channels.Although illustrated with five of each of first gas outlets 208-218 andsecond gas outlets 220-228, gas injection systems in accordance withthis disclosure can include any suitable number of first, second, and/orother gas outlets, corresponding to a number of channels for therespective gases. For example, exemplary systems can include, forexample, about 1-10 channels or include 5, 6, 7, 9, or more channels foreach gas. As illustrated, first gas manifold 206 and/or second gasmanifold 208 can include a loop configuration to facilitate even flowdistribution through the gas channels. Additionally or alternatively,first gas manifold 206 and/or second gas manifold 208 can have arelatively large diameter relative to gas lines 202, 204—e.g., thediameter of first gas manifold 206 and/or second gas manifold 208 can begreater than 2, 3, 4, or 5 times larger than the diameter of line 202and/or line 204. In the illustrated examples, first gas channels andsecond gas channels are alternatingly adjacent each other. However, thisneed not be the case.

As noted above, first gas source 203 and/or second gas source 205 can bea mixture of two or more gases. In such cases, one or more gases, whichmay, in turn, include a mixture of gases—or not, can be supplied fromother sources (not illustrated) to first gas source 203 and/or secondgas source 205 via flow controllers 207-213. When the source gasesupstream of flow controllers 207-213 are not mixtures of gases, flowcontrollers 207-209 can suitably be mass flow controllers. By way ofexamples, one or more of flow controllers 207-213 can control a flowrate of a carrier gas to first gas source 203 and/or second gas source205. Flow controllers 207-213 can be coupled to gas sources 302-308,described in more detail below.

Gas injection system 200 additionally includes a plurality of flowsensors 230-248 coupled to first and second gas outlets 210-228. In theillustrated example, each first and second gas outlets 210-228 iscoupled to a single flow sensor 230-248. However, in some cases, it maybe desirable to have some gas outlets that are not coupled to a flowsensor and/or to have some gas outlets that are coupled to more than oneflow sensor.

Flow sensors 230-248 can be used to monitor flow rates of gas mixturesand to provide real-time and/or historical flow rate information to auser for each channel—e.g., using a graphical user interface.Additionally or alternatively, flow sensors 230-248 can be coupled to acontroller (e.g., controller 294) and to gas valves 250-268 to providecontrolled flow ratio of the gases through gas valves 250-268. Byplacing at least one flow sensor 230-248 in each gas channel, the flowratio (e.g., relative flow rate) of gas through each channel can bemeasured and controlled, regardless of the gas composition. Exemplaryflow sensors 230-248 can be or include various flow sensors, e.g.,thermal mass flow sensors, pressure drop based flow sensors, or thelike.

Gas valves 250-268 may allow the control of gas flow through one or moregas outlets 210-228 (e.g., each flow rate through gas outlets 210-228may be individually controlled, or groups of gas outlets may becontrolled, such as all gas outlets coupled to first gas manifold 206and first gas source 203, or to second gas manifold 208 and second gassource 205). Gas valves 250-268 can include any suitable device to meterflow of a gas. In accordance with various embodiments of the disclosure,gas valves 250-268 each comprise proportional valves, such as solenoidvalves, pneumatic valves, or piezoelectric valves. A valve with arelatively high (e.g., 0.021-0.14) flow coefficient (Cv) may be selectedto reduce chocking downstream. Gas valves 250-268 may desirably operateunder closed-loop control, but may also be capable (e.g., additionally)of operating under open-loop control.

Flow sensors 230-248 and gas valves 250-268 can initially form part of,for example, a mass flow controller (e.g., an off-the-shelf mass flowcontroller), wherein the control function of the valve is replaced bycontroller 294. For example, flow meter 230 and gas valve 250 can formor be part of a mass flow controller 270 that is set to operate inopen-loop mode and wherein controller 294 provides closed-loop controlof valves 250-268. Flow sensors 232-248 and gas valves 252-268 cansimilarly form or be part of a mass flow controller 272-288. Thisconfiguration allows for implementation in standard reactorconfigurations and/or for use of readily-available mass flow controllersand flow sensors and valves.

Gas valves 250-268 can be coupled to a reaction chamber 290 via a flange292. Additional line (e.g., tubing) and suitable connectors can be usedto couple gas valves 250-268 to flange 292. Exemplary flange 292includes flange gas channels to maintain the channels until therespective gases exit into reaction chamber 290; one exemplary flangegas channel 310 is illustrated in FIG. 3. Flange gas channels caninclude expansion areas 312, 314 and respective outlets 316, 318, whichterminate at opposite sides of the flange and adjacent each other. Forexample, the first gas channels, corresponding to first gas streams, canterminate at a first side 296 of flange 293 and the second gas channels,corresponding to second gas streams, can terminate at a second side 298of flange 292.

Gas injection system 200 can optionally include a moisture sample panel.A moisture sample panel can include, for example, one or more pressuretransducers, pneumatic valves, and/or restrictors. An exemplary moisturesample panel is disclosed in U.S. application Ser. No. 15/997,445, filedJun. 4, 2018, and entitled GAS DISTRIBUTION SYSTEM AND REACTOR SYSTEMINCLUDING SAME, the relevant contents of which are hereby incorporatedherein by reference, to the extent such contents do not conflict withthe present disclosure.

Reaction chamber 290 can be formed of, for example, quartz. Exemplaryoperating pressures within reaction chamber 290 during substrateprocessing can range from, for example, about 0.5 mTorr to about 780Torr. By way of examples, the pressure can range from about 2 mTorr toabout 780 Torr. In accordance with exemplary embodiments of thedisclosure, system 200 can provide desired, stable, independent flowcontrol within each channel over such pressure ranges.

Controller 294 can be configured to perform various functions and/orsteps as described herein. Controller 294 can include one or moremicroprocessors, memory elements, and/or switching to perform thevarious functions. Although illustrated as a single unit, controller 294can alternatively comprise multiple devices. By way of examples,controller 294 can be used to control flow of gas from first gas source203 and/or second gas source 205 in a plurality of gas channels, whichcan span between, for example, respective first or second gas outlets,optionally through flange 292, and optionally to reaction chamber 290.Controller 294 can be configured to provide open-loop and/or closed-loopflow control using, for example, the same hardware. In particular,controller 294 can be configured to provide desired ratios of a totalflow of a respective gas (e.g., from first gas source 203 or second gassource 205) in each of the channels coupled to the respective sources.In accordance with various examples of the disclosure, controller 294includes proportional-integral-derivative (PID) controllers, which allowindependent, closed-loop control of the various controllable valvesdescribed herein, including gas valves 250-268. With PID closed-loopcontrol, system 200 can dynamically adjust flows in one or more (e.g.,all) gas channels to set points and/or provide stable, especiallyinitial, flow rates of gases to reaction chamber 290 when switchingbetween gas sources and/or when the operating pressure is relativelyhigh (e.g., near atmospheric pressure). The closed-loop control allowsfor automatic and stable control of flow rates through each channel overa wide variety of pressure ranges, such as those set forth herein. Theclosed-loop control further allows for control without tool matching,which is often required for traditional systems. By way of example,using PID control, an initial set point for each controlled valve can beselected. Flow ratio feedback from an output of each flow sensor coupledto the controllable valve can then be used in connection with a PIDcontroller of controller 294 to control the desired set point (i.e.,flow ratio) of each of the controlled valves.

Systems and methods described herein improved the concentration profileof a dopant within a film deposited using the systems and/or methods. Inaccordance with examples of the disclosure, a non-uniformity of aconcertation of a dopant from center to edge of the substrate variedless than 10%, less than 7.5%, and less than 6%—even with the relativelyhigh concentrations of dopant.

As noted above, in accordance with at least one embodiment of thedisclosure, first gas inlet 202 can receive a first gas comprising afirst precursor and a dopant source, and second gas inlet 204 canreceives a second gas comprising the first precursor or a secondprecursor and an etchant. In this case, gas source 302 can include aprecursor as described herein, gas source 304 can include a dopantsource as described herein, gas source 306 can be or include gas source302 or another (e.g., second) precursor gas source, and gas source 308can include an etchant. FIG. 4 illustrates an example of a shared gassource 302. Flow controllers 207 and 211 are coupled to shared gassource 302. When gas sources 302 and 306 are the same/shared source, agas ratio between first gas source 203 and second gas source 205 canvary from, for example, about 0.8 to about 0.9, about 0.9 to about 1.0,or about 1.0 to about 1.3.

In accordance with other examples of the disclosure, first gas inlet 215can receive a first gas comprising an etchant and a dopant source, andsecond gas inlet 217 can receive a second gas comprising a precursor. Inthis case, gas source 302 can include an etchant as described herein,gas source 304 can include a dopant source as described herein, gassource 306 can include a precursor source as described herein, and gassource 308 can include a carrier gas. In this case, a flowrate of thecarrier gas and the precursor gas can each be independently controlledto provide additional control over the composition films deposited.

In various embodiments, the systems and methods herein may mitigateagainst undesired effects to a film toward the edge of a substrate(e.g., edge roll-down), as well as improve the desired germaniumconcentration in the film. For example, including a compound common toboth the first gas and the second gas (e.g., having a common precursorand/or etchant between the first gas from first gas source 203 and thesecond gas from second gas source 205) during substrate processing mayachieve beneficial results. As a further example, first gas source 203and second gas source 205 may both comprise and deliver hydrogenchloride and/or germane to reaction chamber 290.

With reference to Table 1 and FIGS. 5A-5C, four examples of thedisclosure are described, in which gases comprising various componentsbeing sent through the first gas source and the second gas source of areactor system (e.g., first gas source 203 and second gas source 205shown in FIG. 2), which were compared with one another. In the exampledepicted by data sets 512, 522, the first gas and the second gas do nothave a component in common, while in the other three experiments, thefirst gas comprises a component in common with the second gas. Data sets512 and 522 are shown in all three charts 500, 550, and 600. The topplot in each chart (top plots 510, 560, and 610) shows the germaniumcontent in a silicon germanium layer deposited on a substrate as afunction of the position on the substrate (the “0” position on thex-axis indicates the middle of the substrate, and moving along thex-axis in either direction indicates moving from the substrate centertoward the substrate edge(s)). The bottom plot in each chart (bottomplots 520, 570, and 620) shows the thickness of the silicon germaniumlayer deposited on the substrate as a function of the position on thesubstrate (same x-axis units as for the top plots).

TABLE 1 Gas Gas Flow Ratio Through Data Set Gas Flow Source Gas Outlets512, 522 GeH₄, SiH₄ First 30 9 22 9 30 HCl Second 15.5 23 23 23 15.5514, 524 GeH₄, SiH₄, HCl 59% First 30 9 22 9 30 HCl 41% Second 1 1 96 11 564, 574 GeH₄, SiH₄, HCl 59% First 30 9 22 9 30 HCl 41% Second 1 1 961 1 614, 624 GeH₄, SiH₄, HCl 58.30%   First 30 9 22 9 30 GeH₄ 41.70%  Second 48.5 1 1 1 48.5

As shown in Table 1, data sets 512 and 522 show the results of flowing afirst gas comprising germane (GeH₄) and silane (SiH₄) through a firstgas source, and flowing a second gas comprising hydrogen chloride (HCl)through a second gas source to a reaction chamber. The “Gas Flow” columnof Table 1 indicates the percentage of total gas flow (the total gasflow being the sum of the first gas flow and the second gas flow) madeup by of each of the first gas and the second gas. For example, for datasets 514 and 524, the total gas flow between the first gas and thesecond gas comprises 59% first gas and 41% second gas. Furthermore, inthese examples, the first and second gas sources each have five gasoutlets (e.g., gas outlets 210-228 shown in FIG. 2). Accordingly, the“Flow Ratio Through Gas Outlets” column and sub-columns indicate thepercentage of each gas flowed through each gas outlet. For example, forthe first gas of data sets 512, 522, 30% of the first gas was flowedthrough each of the two outermost gas outlets (i.e., the gas outletsmost proximate the edge of the substrate), 9 percent of the first gaswas flowed through each of two inner gas outlets, and 22 percent of thefirst gas was flowed through a center gas outlet. Similarly, for thesecond gas of data sets 512, 522, 15.5% of the second gas was flowedthrough each of two outermost gas outlets (i.e., the gas outlets mostproximate the edge of the substrate), 23 percent of the second gas wasflowed through each of two inner gas outlets, and 23 percent of thesecond gas was flowed through a center gas outlet. The flow rate and/orflow amount of a gas through any of the gas outlets in a gas source, asdiscussed herein, may be adjusted independently or in conjunction withother gas outlets (e.g., via a respective gas valve 250-268, as shown inFIG. 2).

As can be seen by data set 512, the germanium content in the silicongermanium layer gradually begins to increase from a relatively constantgermanium content around 85 millimeters from the center of thesubstrate. A more desired germanium content configuration in a silicongermanium layer may be one that is relatively constant on the substratefor a long as possible spanning out from the substrate center, and thena sharp increase proximate the substrate edge (thus having a moreconsistent germanium content in the silicon germanium layer across agreater area of the substrate before a sharp increase near the substrateedge). As can be seen by data set 522 (and emphasized by windows 528,578, and 628), the silicon germanium layer thickness increases towardthe edge of the substrate and then tapers as the rate of increasinglayer thickness decreases (i.e., edge roll-down). This thickness patternof a silicon germanium layer may be less desirable than a layerthickness that continues to increase toward the substrate edge and doesnot taper.

Charts 500 and 550, and data sets 514, 524 and 564, 574, shown in Table1 and in FIGS. 5A and 5B, respectively, depict the results of flowing afirst gas comprising germane, silane, and HCl through a first gassource, and flowing a second gas comprising HCl through a second gassource to a reaction chamber. Therefore, the first gas and the secondgas both comprise HCl. The flow percentages and the flow ratio througheach gas outlet are shown in the respective columns of Table 1. Theexample producing data sets 514, 524 comprised a silicon controlledrectifier (SCR) having a top-biased power ratio of 55% top/45% bottom,while the example producing data sets 564, 574 comprised an SCR having abottom-biased power ratio of 42% top/58% bottom. As can be seen throughdata sets 514 and 564, the germanium content in the resulting silicongermanium layers gradually begins to increase from a relatively constantgermanium content around 110 millimeters from the center of thesubstrate. Thus, including a common compound in both the first andsecond gases (e.g., an etchant, such as HCl) resulted in a moreconsistent germanium content in the silicon germanium layer across agreater area of the substrate than that shown in data set 512. As can beseen through data sets 524 and 574 (and emphasized by windows 528 and578), the silicon germanium layer thickness continually increases towardthe edge of the substrate without tapering (i.e., without edgeroll-down). Thus, providing these first and second gases, both sharingat least one compound (e.g., HCl), produced more desirablecharacteristics of the resulting silicon germanium layer than that shownin data set 522.

Chart 600, and data sets 614, 624, shown in Table 1 and in FIG. 6,depict the results of flowing a first gas comprising germane, silane,and HCl through a first gas source, and flowing a second gas comprisinggermane through a second gas source to a reaction chamber. Therefore,the first gas and the second gas both comprise germane. The flowpercentages and the flow ratio through each gas outlet are shown in therespective columns of Table 1. As can be seen through data set 614, thegermanium content in the resulting silicon germanium layer graduallybegins to increase from a relatively constant germanium content around120 millimeters from the center of the substrate. Thus, including acommon compound in both the first and second gases (e.g., a precursor,such as germane) resulted in a more consistent germanium content in thesilicon germanium layer across a greater area of the substrate than thatshown in data set 512. As can be seen through data set 624 (andemphasized by window 628), the silicon germanium layer thicknesscontinually increases toward the edge of the substrate without tapering(i.e., without edge roll-down). Thus, providing these first and secondgases, both sharing at least one compound (e.g., germane) produced moredesirable characteristics of the resulting silicon germanium layer thanthat shown in data set 522.

Although exemplary embodiments of the present disclosure are set forthherein, it should be appreciated that the disclosure is not so limited.For example, although the gas injection and reactor systems aredescribed in connection with various specific configurations, thedisclosure is not necessarily limited to these examples. Variousmodifications, variations, and enhancements of the system and method setforth herein may be made without departing from the spirit and scope ofthe present disclosure.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various systems,components, and configurations, and other features, functions, acts,and/or properties disclosed herein, as well as any and all equivalentsthereof.

We claim:
 1. A gas injection system comprising: a first gas manifoldcomprising a first gas inlet and a plurality of first gas outlets; asecond gas manifold comprising a second gas inlet and a plurality ofsecond gas outlets; a plurality of first gas valves, wherein each of theplurality of first gas outlets is coupled to at least one of theplurality of first gas valves; and a plurality of second gas valves,wherein each of the plurality of second gas outlets is coupled to atleast one of the plurality of second gas valves, wherein the first gasinlet receives a first gas comprising a first precursor and a dopantsource, and wherein the second gas inlet receives a second gascomprising the first precursor or a second precursor and an etchant. 2.The gas injection system of claim 1, wherein the second gas comprisesthe first precursor. The gas injection system of claim 2, furthercomprising a first flow controller coupled to a first precursor sourceand the first gas inlet and a second flow controller coupled to thefirst precursor source and the second gas inlet.
 4. The gas injectionsystem of claim 1, wherein a chemical formula of the first precursor anda chemical formula of the second precursor comprise one or more of thesame elements.
 5. The gas injection system of claim 1, wherein the firstprecursor is selected from the group consisting of trichlorosilane,dichlorosilane, silane, disilane, trisilane, and silicon tetrachloride.6. The gas injection system of claim 1, wherein the dopant is selectedfrom the group consisting of germane, diborane, phosphine, arsine, andphosphorus trichloride.
 7. The gas injection system of claim 1, whereinthe etchant comprises hydrogen chloride.
 8. A gas injection systemcomprising: a first gas manifold comprising a first gas inlet and aplurality of first gas outlets; a second gas manifold comprising asecond gas inlet and a plurality of second gas outlets; a plurality offirst gas valves, wherein each of the plurality of first gas outlets iscoupled to at least one of the plurality of first gas valves; and aplurality of second gas valves, wherein each of the plurality of secondgas outlets is coupled to at least one of the plurality of second gasvalves, wherein the first gas inlet receives a first gas comprising anetchant and a dopant source, and wherein the second gas inlet receives asecond gas comprising a precursor.
 9. The gas injection system of claim8, wherein the second gas further comprises a carrier gas.
 10. The gasinjection system of claim 8, wherein the first gas further comprises acarrier gas.
 11. The gas injection system of claim 9, further comprisinga flow controller to control a flowrate of the carrier gas.
 12. The gasinjection system of claim 9, wherein the carrier gas is selected fromthe group consisting of nitrogen, hydrogen, and helium.
 13. The gasinjection system of claim 8, wherein the precursor is selected from thegroup consisting of trichlorosilane, dichlorosilane, silane, disilane,trisilane, silicon tetrachloride.
 14. The gas injection system of claim8, wherein the dopant is selected from the group consisting of germane,diborane, phosphine, arsine, phosphorus trichloride.
 15. A reactorsystem comprising the gas injection system of claim
 1. 16. The reactorsystem of claim 15, further comprising a susceptor, wherein thesusceptor rotates at a rotational speed of about 60 to about 30, about30 to about 15, or about 15 to about 5 rotations per minute.
 17. Amethod of depositing material on a surface of a substrate within areaction chamber using the gas injection system of claim
 1. 18. Themethod of claim 17, further comprising a step of rotating a susceptor ata rotational speed of about 60 to about 30, about 30 to about 15, orabout 15 to about 5 rotations per minute.
 19. The method of claim 17,wherein a temperature of a susceptor is 500 to about 600, about 600 toabout 700, or about 700 to about 800 degrees Celsius.
 20. The method ofclaim 17, wherein a pressure within the reaction chamber is betweenabout 2 mTorr to about 780 Torr.
 21. The method of claim 17, wherein thefirst gas and the second gas comprise a common component.